One day in 2003, in the lead up to the Iraq War, British intelligence specialist Katharine Gun (Keira Knightley) receives a memo from the NSA with a shocking directive: the United States is enlisting Britain's help in collecting compromising information on U.N. Security Council members to blackmail them into voting in favor of an invasion of Iraq. Unable to stand by and watch the world be rushed into war, Gun makes the gut-wrenching decision to defy her government and leak the memo to the press.